The invention relates generally to image re-identification and more particularly to a technique for performing person re-identification based on the overall appearance of an individual.
A number of applications require the ability to re-identify an individual across multiple disjointed fields of view. Re-identification is the ability to identify a previously observed individual. In many surveillance applications, there is a need to be able to re-identify an individual based on their appearance during that day. Re-identification techniques may also be used in security applications, forensic applications, for the identification of missing people and for robust site wide tracking in crowded environments such as mass transit and airports.
As will be appreciated by those skilled in the art, person re-identification typically involves establishing correspondences between parts of images and generating invariant signatures for comparing the corresponding parts. Several approaches have been proposed where invariant signatures based on a global appearance of an individual are compared. For example, a color histogram of the region below the face, or clothing color descriptors, may serve as a signature for comparison. Re-identification may then be achieved by comparing adjusted color histograms.
In contrast to global appearance-based methods, a number of object recognition techniques such as interest point operators and model fitting have been developed to establish correspondences between objects. These techniques have demonstrated that comparing multiple local signatures can be effective in exploiting spatial correspondences between individuals and achieving robustness regarding local variation in appearance.
It would be desirable to develop a technique to perform person re-identification using model fitting to establish spatial correspondences between individuals. In addition, it would be desirable to develop a technique to perform person re-identification using signatures that are invariant to the dynamic nature of clothing, and changes in illumination conditions, and pose.